Comparative study of two laser Doppler blood flowmeters

Abstract

A new infrared laser Doppler blood flow instrument (Moor MBF3D) was evaluated using an in vitro model allowing measurements over a range of flow velocities and concentrations. The responses correlated well (r = 0.96, p less than 0.01) with those obtained simultaneously using a Perimed PF3 laser Doppler instrument. The different processing bandwidths of the instruments were investigated and the wideband mode of operation is recommended for flow measurements where there may be fast moving red blood cells (rbcs). The infrared instrument is capable of dual-channel operation, and the two channels are shown to respond almost identically for similar changes in blood flow through the in vitro model (r = 0.999, p less than 0.01). The main advantage of the dual-channel instrument is that continuous measurements may be made simultaneously at two different skin sites allowing dynamic flow responses to be compared.

Laser Doppler Flow Imaging of Open Lower Leg Fractures in an Animal Experimental Model

“…Using 2 independent probes with online reading and analysis, matched with our histomorphological data, valid findings resulted. 26 When delayed plastic covering could not reconstitute cortical perfusion to sufficient levels (group B), early closure increased perfusion continuously to week 16, by which time near-normal values were reached (group A). 26 As stated by Smahel et al 24 a neoperiostal lining forms only after week 8 in cases of sufficient perfusion; this finding was confirmed by our investigation.…”

Review of methodological developments in laser Doppler flowmetry

“…Evaluation of the processor by Nilsson [27] and also by Ahn et al [64] showed that this correction method works well till a volume fraction of around 1% is reached. A later study by Barnett et al [85] showed, however, that at higher perfusion rates this processor underestimates the flow. Petoukhova et al [86] did a comparative study of the output flow signal of two instruments, one with a linearizer and one without.…”

“…This suggested that the linearization algorithm was not influencing the perfusion signal for a range of physiologically relevant flow values. The fact that the concentration signal was becoming saturated at higher flow values [86,87] and that the response of the power spectral density algorithm was extremely poor above concentrations of 0.2% volume fraction of RBCs [85], questions the usefulness of using the linearization algorithm under these conditions.…”

Speckles in laser Doppler perfusion imaging

“…Evaluation of the processor by Nilsson [27] and also by Ahn et al [64] showed that this correction method works well till a volume fraction of around 1%. But in a later study by Barnett et al [85] showed that at higher perfusion rates this processor under estimates the flow. Petoukhova et al…”

“…This suggests that the linearization algorithm is not influencing the perfusion signal for a range physiologically relevant flow values. The fact that the concentration signal is getting saturated at higher flow values [86] and that the response of the power spectral density algorithm is extremely poor above concentrations of 0.2% volume fraction of RBC [85], questions the usefulness of using the linearization algorithm under these conditions.…”